摘要： 建立了自动电位滴定法测定聚醚多元醇混合物羟值的方法。样品中羟基与对-甲苯磺酰异氰酸酯(TSI)反应形成酸性氨基甲酸酯,加入少量的水使过量的TSI形成磺酰胺,用四丁基氢氧化铵(Bu₄NOH)滴定形成的酸性氨基甲酸酯,计算羟值的含量。测试结果与邻苯二甲酸酐酰化法基本一致,该方法能避免使用有毒且味道难闻的吡啶试剂,且方法简便、快速、准确,对环境友好。

关键词: 聚醚多元醇, 羟值, 电位滴定法

Abstract: A novel method has been developed for the determination of hydroxyl value of polyether polyol composition. The hydroxyl group is reacted with excess p-toluene sulfonyl isocyanate (TSD)to form an acidic carbamate Wherein, water is added to convert unreacted isocyanate to sulfonamide, followed by direct potentiometric titration of the acidic carbamate with tetrabutylammonium hydroxide (Bu₄NOH) in non aqueous medium. Compared with international general method (e.g., phthalic anhydride acylation method), the novel method avoids the use of the poisonous and malodorous pyridine reagent and gives the consistent testing results. Moreover, the novel method is convenient, quick, accurate and environmental friendly,suitable for determination of hydroxyl value in polyether polyol composition.

Key words: polyether polyol, hydroxyl number, potentiometric titration